taters-You don't need to buy anything to check the speed. A download-and-print strobe is available here:
http://www.conradhoffman.com/chsw.htm
and any light source will work-fluorescent works best, but incandescent works also. The main advantage of the 100.00 KAB is that it doesn't rely on your home AC-generated 60hz frequency which may be (very) slightly off. If the strobe shows that the speed is off, you can make slight corrections without a SDS by moviing the belt up or down the motor pulley-it's slightly graduated in size for this specific purpose.
http://www.conradhoffman.com/chsw.htm
and any light source will work-fluorescent works best, but incandescent works also. The main advantage of the 100.00 KAB is that it doesn't rely on your home AC-generated 60hz frequency which may be (very) slightly off. If the strobe shows that the speed is off, you can make slight corrections without a SDS by moviing the belt up or down the motor pulley-it's slightly graduated in size for this specific purpose.